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O. T Swan.

Notes on the proposed introduction of the French System of treating poles by the Boricherix process for use on the National forests online

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UNITED STATES DEPARTMENT OF AGRICULTURE
FOREST SERVICE



NOTES ON THE PROPOSED INTRODUCTION OF THE FRENCH SB TEE
OF TREATING POLES BY THE BOUCHERIX PROCESS FOR
USE ON TJLE NATIONAL FORESTS

By

0. T. Swan
/

Forest Assistant, Forest Service
}1arch, 1911.



T/



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APPLICABILITY OF THE BOUCHERIE SYSTEt! OP POLE
PRESERVATION TO THE NATIONAL FORESTS

By 0. T. Swan
Forest Assistant, Forest Service

Introduction.

in 1910 the writer made a study of the methods
and results of treating poles in several European coun-
tries. The Boucherie process in common use in France
seemed applicable to certain conditions in the United
States and especially to the National Forests* In June
1910, the subject was taken up with Assistant District
Forester of District 5, Mr. C. Stowell Smith, who imme-
diate^ nav; the possibilities of the method and made
plans to test it in California. Later the experiments
were deferred until the summer of 1911.

The Boucherie process aims to fill the sapwood
of susceptible species with a water solution of an anti-
septic salt, generally copper sulpJakfefc. This is brought
about by applying the solution under a gravity pressure
of 20 to 30 feet to the butt of a freshly cut pole. The
antiseptic solution is thus forced from end to end of the
pole.

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General .

In France the telephone and telegraph lines are
in charge of the federal department of Posts and Telegraphs.
From 250,000 to 300,000 poles per year are consumed in the
Government lines and practically all of these are treated
with a solution of copper sulphate under what is known as
the Boucherie process. Other preservatives are used to a
comparatively small extent for experimental purposes. .

Previous to 187^, creosote was used to a great
extent for treating poles in France. Since that time the
use of copper sulphate has become general for the treat-
ment of poles. Creosote was objected to because the
workmen found it very disagreeable and considerable trouble
with them resulted. The men sometimes refused to handle
the timber except at high wages. There was also trouble
because creosote contaminated the water supply near places
where* treated timber was set.

The Boucherie process/is not a revival of a dead
process , but is is a method which has been in continuous
and large use in Europe since it first became generally
known. Toiay about one- third of the poles used in Germany
and practically all of those used in France are treated
under variations of this system. It can not be used in
any climate rr v/lth any species of timber. For its

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successful operation a temperature above freezing is nec-
essary and a species of timbea? largely sapwood. The sys-
tem lias the advantage of treating the entire pole at a
very low cost. Further, only a relatively inexpensive
equipment to do this work is required and after it is
once in operation very little technical supervision is
necessary. Copper sulphate is inexpensive and the amount
necessary to treat a large number of poles can be verjr
cheaply transported in the crystal form. For this reason
the method seems well adapted to certain parts of the
United States and espeo.uv.Liy some of the national Forests.

It will be necessc?.ry to make a number of exper-
iments to find out just what success may be had in treat-
ing different American species since nothing has been at-
tempted previously along this line.

Advantages and Disadvantages of the Use of Copper Sulphate.

A solution of copper sulphate is the solution
commonly employed in this process. Among the disadvantages
of the use of copper sulphate is the fact that it attacks
iron, resulting in the formation of iron sulphate which
destroys organic matter, but other metals which will not
be attacked by the sulphate may be used in the equipment
of the plant. The preservative action of copper sulphate
is weakened by the presence of alkaline salts in the soil
in which the poles are set. It is dissolved by rain water
charged with carbonic acid. The water used in mixing the

solution must be very pure.

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The Boucherie system has the advantage that
inexpensive preservatives way be employed. Since they
are used in solution the transportation of quantities
sufficient for the treatment of a large number of poles
is relatively eheap. The preservative for many polesfis
easily and cheaply stored. It is claimed that copper
sulphate decreases the combustibility of the wood. The pres-
ence of the copper in treated wood is often apparent at
sight, and is also proved by very easy and certain chemi-
cal tests. The equipment is relatively cheap, but a
small anount of labor is required, and very little tech-
nical supervision in nee', osary.

Plant Required.

The plant necessary for treating poles by the
Boucherie process consists of a tank of the copper sulphate
solution raised on a tower or other support at a sufficient
elevation to force the solution through the poles after
a suitable apparatus communicating with the elevated tank
has been connected at the butt of each pole. In order to
supply the reservoir solution tank on the tower with addi-<
tional quantities of the preservative, a mixing tank is
set up at the foot of the tower. Here the proper pro-
portions of pure water and copper sulphate are mixed, form-
ing the treating solution. A hand pump or one run by an
electric motor is generally installed to carry the solution

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froja the mixing tank to the elevated storage tank. It is
of course necessary that the tanks, pumps, and piping "be
made of material that will not be Attacked by the copper
sulphate . The elevation of the storage tank is generally
tlr-i same as the length of the longest pole to be treated.

A lead pipe runs from the elevated storage
tank to a general supply pipe running the length of the
skidways and from Hi is the rubber tube is fitted with a
hollow wooden pin which is either inserted into a solid
block of wood, which acts as a stopper when no poles are
being treated, or into the treating device clamped on the
butt of each pole.

In order to force the fluid from one end of the
pole to the other it is necessary to use an inexpensive
device which may be fastened to the butt end of the pole.
This part of the equipment consists of a solid v/ooden sec-
tion a little larger than the butt end of the pole, gen-
erally made of one piece of oak or elm planking reinforced
by a small strip of wood, the notched ends of which project
on both sides of the wooden butt plate. The plate is held
in position on the end of the pole by means of two iron
pins, one of which is bent at right angles and sharpened
in order that it may be driven firmly into the pole, while
the other end which engages the notched strip of wood
previously mentioned, is threaded and carries a washer and
nut. In using this device, a circle of packing or a vul-
canized rubber ring is placed between the wooden disc and

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the butt of the pole in such a manner as co form a chamber
at least 1/2" deep "between the end. of x-he pole and the disc

The pins carrying the washer and nut are inserted in the

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notches of this "butt equipment with their sharpened ends
driven deep into the pole. The nuts are then screwed up
very tightly, making the narrow chamber between the pole
and disc practically water-tight. There is a small hole
through the wooden plate and into this the hollow wooden
piece at the end of the rubber tubing is inserted. This
establishes the connection between the elevated storage
tank and the fluid-tight chamber at the butt of the pole.

Proceed of Treatment.

The plant should be located on a level area and
in case about 7,000 poles a 2rear are to be treated, it is
usual to have a space of about 55>000 square feet or an
area 330 feet long by 165 feet wide. Such plants have a
capacity of about 25 to 5 poles a day. The plants must,
of course, be located near the place where the poles are
cut.

Per this reason the treatment of poles must be
oommenced within a very few days of the time of cutting,
the length of time depending upon the season of the year.
During the surame^, treatments must begin within 3 r 4
days, while in the winter time they need not conmence

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I'or 8 or 10 da3^s~ The reason for thic ir< v,r.=*,t the poles
must have seasoned as little as pooe i'b." 1 u ^ retaining their

normal quantity of sap and water. If any checks develop

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on the sides of the poles or through the "bark the pole
is in unsatisfactory shape for treatment, sines the trea-
ing fluid may escape through these "breaks. Pur the r, if
part of the sap has been lost through seasoning, it is found
that the treatment is apt to "be unsatisfactory through the
pole. Therefore, the poles are hauled from the woods to
the treat. ing skidways as soon as possible after cutting,
talc.iiif precautions not to injure the bark while transport-
ing them orlnoe the "bark is left on during the treatment.

The poles are placed on the treating skidways
in a s. ingle even layer, the skids being so placed that
there is a s light incline from the bottom of the pole to-
ward the top. It is specified that the skids must be of
sound, peeled timber, and must be removed as soon as they
show signs of decay. A section of the butt of each pole
is cirh off in order to give a fresh and smooth surface
for the connection of the apparatus to the pole. The
butt of each pole is immediately fitted with the butt
plate and connected with the large supply pipe mining
along the length of each sic idway and described in the
preceding pagiss.

There is some loss of preservative fluid
at first, but this gradually lessens. Within three or

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four days the copper sulphate begins to d: v ip from the wp
end of the pole. In order to insure a thorough treatment
this is allowed to continue for several days longer or
until the solution lost at the top of the pole is of the
same composition as that injected. Tlie entire time for
treating the poles may require a week or 10 days. Ho at-
tempt is made to recover any of the copper sulphate which
is lost in the drip from the top of the poles. In fact,
the French specifications expressly prohibit its use in
further operations. At the end of the week or ten days the
top end of the pole is a very green copper sulphate color.

The solution which is used for this treatment
consists of 1 kilogram of copper sulphate to 100 kilograns
of water. This chemical must be crystalized ani must not

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contain more than 1 per cent of foreign matter, while the
strength in pure copper must not "be less than 24-1/2 per
cent. The height of the surface of the liquid in the
elevated tank varies according to the maximum length of
the pole v/hich it is proposed to treat at the plant. The

French practice is from 6 to 6-1/2 meters for poles 6-1/2

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meters long, aid 10 meters for poles up to 12 meters long,

and about 12-1/2 meters for poles 1J meters long.

After treatment the poles are seasoned for 30
days with the bark on, permitting the solution to work



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within the pole. If the "bark in removed. l;:.Oie-.lJ at e'Ly ; vao
poles are apt to take on an undesirable darlc or black color.
At the end of the 50 days , the bark is renoved fron the
poles and the top of each is pointed, cutting away from 6
to 12 inches of wood at that end. The freshly exposed sur-
face at the top of the pole is then tested by the Govern-
ment inspectors with a chemical reagent which gives a pink
or reddish-brown color to the treated wood. (90 grams potas-
sium ferrocyanide to 100 liters of water). From this color
it is then possible to tell whether the treatment is sat-
isfactory, further, in order to be sure that the trealanent
is even and that the poles were not held too long before the
treatasnt began, the Government inspectors have the right to
cut up f:i.ve poles per thousand and reject the entire lot if
one of the five poles is below the requirements.

After the poles are accepted they are stamped
wi th. initials or marks indicating Government ownership and
the name of the contractors who did the treating; also
the date. The contract ors must guarantee the poles for
five years beginning with the first of January following
the acceptance of the poles.

After the poles are accepted they are piled in
high open piles for further seasoning, as shown in the
photograph.



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Specif icat ions .

The specifications governing poles treated "b;>
the Boucherie process for the French government include
the following provisions:

Contracts for treated poles are made with the
various companies supply ing such material after competi-
tive "bids have "been obtained.

In general only coniferous species of wood may
"be used, such as pine, fir, spruce, and larch, while the
contract may specify only pine or fir. Anerican white pine
and Austrian pine, variety larico, are specifically excluded,
; r aritine pine which lias been bled for turpentine may also
be used, provided the 63$) osed surface is not more than two
feet long. ITo fire-killed trees can be used, Poles must
be cut from healthy trees and the diameter of the heart-
wood at the top of the pole must not exceed two-thirds of

the top diameter. The contract specifies the sizes and

l;e -cf ?,qund
the percentage of each size required, giving the length

of the pole, its circu inference at 1 meter from the butt
end and at the top.

The solution used in treating the poles shall
consist of 1 kilogram of copper salphate for each 100
liters of pure water. The salt must be in the crystal-
lized state and must not contain more than 1 per cent
of foreign matter. The strength of the crystallized cop-
per sulphate in pure copper must not be less than 24. 5
per cent.

-10-



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Provisions are ind uded for a minimum height 01
the reservoir of the solution above the poles, which, o :'
course, controls the pressure tinder which the n Glut a en is
applied. In general, this height equals the length of the
poles to be treated, except in the case of very long poles
when the height of the reservoir is proper tj.ona.lly bomewlmt
less. The solution must be injected from ths butt ond of
the pole and must penetrate the entire pole in a uniform
manner. The Government reserves the right to cut up
any five poles selected from each thousand treated in order
to see whether the penetration is satis factory. If cue
pole out of the five selected is found to be improperly
treated, the entire allotment may be rejected.

Thirty days after the poles are treated, but
not sooner, they shall be peeled, shaved, and pointed at
the top end. All refuse must be removed from the neigh-
borhood of the skidways. The skidways must be of sound
barked wood and must be replaced by the contractors at the
first sign of decay.

For failure to comply with any of these provi-
sions the contractor subjects himself to the possibility
of the refusal of all poles which have been treated or
which are being treated. The Oovernmai t will pay for not
exceeding JOO of the test poles which have been destroyed,
irrespective of the total number of poles in the con-
tractor's allotment. The remaining poles destroyed for in-
spection purposes shall be paid for by the contractor.

-11-



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In case tlie treating yard is more than three kil-
ometers from any habitable place, the contractor must pro-
vide transportation as often as 4 times per day, if re-
quired, to Government inspectors* Special provisions
of a precautionary nature are also included in each con-
tract according to the peculiar circumstances. The con-
tractor shall be responsible for the perfect preservation <
the treated poles for five years from the first day of
January following the delivery of the material to the C-ov-



ernment.

following Btateemant ^bows tin* average lit" a uf

Cost.

un^-r pcov, uecu

A plant having a capacity of about 20,000 poles
a year can be built in France for '"'1200 Copper sulphate
is worth about 4-1/2 cents a pound in that country and it
can probably be obtained cheaper in the United States if
used in quantities. The cost of treating poles, includ-
ing handling, runs from 50 to 80 cents for poles from 22
to 35 feet long.

Value of the Treatments.

Pine poles treated with copper sulphate last
from six months ,o more than 2 5 years according to the
character of the soil in which they are- placed. But little
is gained if the poles are in situations unfavorable to
the treatment. Very wet locations, soils containing lime,
and sandy soils are to be avoided.

-12-



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French officials state that they find the aver-
age life of their poles treated v/ith "this preservative t .t
about 18 years in soil adapted to the treatment.

The average life secured in Germany, as shown
elsewhere in this report, is 11.7 years. But this figure
averages all conditions and grades of copper sulphate
treatment. It is well understood that poles treated
with zinc chloride should not be set in swamps "but other
and analogous conditions in the soil especially detri-
mental to copper sulphate have in many cases "been disregarded.

The following statement shows the average life of
poles in 30 representative lines in France under poor, medium,


1

Online LibraryO. T SwanNotes on the proposed introduction of the French System of treating poles by the Boricherix process for use on the National forests → online text (page 1 of 2)